Electrical switching apparatus



flay 15,1934.

w. UEBERMUTH 1,959,183. ELECTRICAL SWITCHING APPARATUS Filed Sept. 219:0

His ATTor-ne gu Patented May 15, 1934 UNITED, STATES 1,959,183ELECTRICAL SWITCHING APPARATUS Werner Uebermuth, Oberschoneweide,Germany,

assignor to General Electric Company, a corporation of New YorkApplication September 2, 1930, Serial No. 479,162

In Germany October 31, 1929 '4 Claims. (Cl. 200-148) Myinvention'relates toelectrical switching apparatus and more particularlyto high tension switching apparatus of the type utilizing a fluid underpressure for extinguishing arcing during interruption of the circuit Inthe interruption of polyphase currents and also-oi single-phase currentsat high voltages, compressed gas or air-blast switches have been usedcomprising several individual switch units.

In this arrangement the points of current interruption of the individualswitches are arranged insuch a mannerthat the exhaust gases evolvedduring the switching operation may flow away freely toward the otherswitch units. These gases are highly heated and as is wellknown, greatlydecrease the dielectric strength of the surrounding air. Y Consequently,measures must be taken so that the switch gases from individual poles ofthe switch do not come into contact with one another to cause flashoversor interphase short circuits.

In accordance with the present invention, this problem is solved byarranging the individual switch poles obliquely in relation to oneanother,

the points of current interruption being remote- 1y located with respectto each other at the free or outer ends of the arms ot'the angle formedby the switch poles. In this arrangement, the switch gases radiate fromthe individual poles indiverging directions and rapidly dissipate in theatmosphere so that there is little occasion for the gases to break downthe-dielectric strength of the air beween poles. Also, the points ofhighest potential are remotely positioned with respect to each other asc mpared with poles arranged in parallel relation for example.

In th operation of switchgear of the air-blast type it is also importantthat a swich comprising several individual switch units be actuatedduring 40 interruption so thatthe moving contacts open simultaneouslywith great accuracy. If a special mechanism were provided for each pointof interruption, a relatively complicated switching apparatus wouldresult in order to establish with 46 certainty simultaneously opening atthe individual points of interruption. If, on the other hand, when usinga common operating member, the movable contacts of the interruptionpoints are connected by a transverse or bridging arrange- 50 ment,mechanical jamming or binding may occur during the switching operationas a result of elastic deformations of the entire construction. Thesemechanical diiliculties are avoided in the oblique arrangement oi" theindividual switches 1 above referred to in accordance with a furtheraspect of the present invention, by the use of a common centrallylocated driving or operating member with which the movable contacts arepivotally connected through guide rods. A further advantage of thisarrangement is that the conduction and distribution of the pressuregases for extinguishing the arcs can be effected from a common gear ormechanism casing. Also, for giiiding the compressed air, as well as forcarrying out of the switching operation and also for extinguishing thearcs, but one'individual pressure gas valve is required for the sourceof pressure and insulated pressure gas pipes to the points ofinterruption are rendered unnecessary. In order to avoid transmission ofa severe thrust to the piston in its limited position, the pressure gasserving to eiiect the opening movement is suitably throttled during thetravel of the piston so that the driving force on the piston becomessmaller with the increase in stroke. The oblique arrangement of theindividual poles has been shown to be advantageous when they areconnested in series, as must be the case for high voltages. 'In thiscase, only fixed connecting lines are between the stationary contacts,so that the flow of curren need not take place through a movable currentbridging member.

Referring to the drawing the single figure thereof is an elevationalsectional view of a compressed gas circuit breaker embodying myinvention.

By way of example, my invention is represented in a pressure gas switchof the air-blast type comprising concentric contact surfaces, betweenwhich a gas may be directed at high pressure for extinguishing the arc,there being two interrupt-- ing points per phase connected in series.The outer stationary contacts are represented at 1 and 2 to which theincoming and outgoing lines 3 and 4 are connected. The movable contacts5 and 6 are adapted to slide in and be guided by the resilient andflexible contacts 7 and 8'which are provided with suitable springs andguide pieces. The guiding contacts 7 and 8 are electrically connected asby the stationary conductor 9 for completing the series connection.between the contacts 1 and 2. l i

Between the contacts 1 and'7, and 2 and 8 are disposed tubular. orcylindrical insulating members 10 and 11 forming longitudinal passagesthrough which gas may be directed across the contacts during separationthereof, which are so designed that when the switch is opened theinsulating structure is able towithstand the compressive and otherstresses set up therein. The

thereof are each moved in a straight line in the passages in thecorresponding insulating tubes 12 and 13 by means of insulating rods 14and 15 which are connected respectively to the cross head members 16 and17 guided within the extensions 18 and 19. The connecting rods 20 and 21for the cross head members are pivotally secured to a hollow piston rod22 comprising a driving member which is guided by the stationary hollowrod 23 provided with the lateral openings or ports 24.

In operating the switch compressed air or other suitable gas is admittedfrom a suitable source of pressure (not shown) through the opening 25 inthe casing 26 and acts on the piston 27 so as to force it downwardly.The gas is directed to the working face of the piston through the ports24,

the hollow piston rod 22 and the opening 28.-

That part of the cylinder 29 located at the opposite or exhaust side ofthe piston 2'7 is of course simultaneously evacuated during the openingstroke. During the downward stroke it will he :noted that the piston rod22 in the manner of-a slide valve shuts off successively the ports 24 inthe tube 23 so that the air supply to the operating piston is throttledand gradually ceases. Accordingly, the force acting on the piston at theend of the stroke is small and insuflicient to set up severe stresses inthe mechanism due to impact at the limiting position" of the piston.

Simultaneous with the operation of the piston 27, the compressed air isdirected into the longitudinal passages from the casing 26 and iiowspast the cross head members 16 and 17 which do not appreciably obstructthe flow of gas through the passages in the extensions 18 and 19, andthe insulation cylinders 12, 10 and 13, 11 to the points of interruption1 and 2, so that the air blast across the contacts takes place at themoment of high speed separation. Upon separation of the coactvingcontactsi, 5 and 2, 6 the consequent arcing between these contacts iseffectively extinguished by the blast of air directed longitudinally ofthe movable contacts so as to pass across the arcing surfaces of thecontacts. The heated air or other extinguishing gas is accordinglyexhausted from the individual switch units at high velocity and due tothe diverging directions of the, air blasts, the gases are effectivelydissipated without danger of flashover between the units.

The switching-in or closing movement is efthe interconnectingcross headand connecting rod mechanism.

It shall be understood that my inventionv is not limited to specificdetails of construction and arrangement thereof herein illustrated, andthat changes and modifications may occur to one skilled in the artwithout departing from the spirit of my invention. I

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is: a

1. A circuit breaker unit of the gas blast type wherein a 'singlesourceof gas pressure is utilized to efiect opening of the circuit andinterruption of arcing including a plurality of stationary and movablecontactsand structure forming longitudinal passages through which gasunder pressure may be directed to interrupt arcing between the coacting'contact surfaces, said movable contacts adapted to move during openingof the breaker in a direction substantially parallel with movablecontacts 5 and 6 during the opening the flow of gas through saidpassages, operating means for the movablecontacts guided for movementwithin said passages, an operating piston effecting simultaneous openingof said movable contacts, and slide valve means connected to said pistoncontrolling communication between a source of pressure and saidoperating piston in accordance with circuit opening movement, saidsource of. pressure likewise being in communication with said passagesfor conourrentlycausing flow of gas at high velocity across theseparating contact surfaces.

2. In a circuit breaker of the gas 'blast type wherein a single sourceof gas pressure is utilized to effect opening of the circuit and.interruption of arcing comprising a'plurality of stationary and. movablecontacts and structure, forming longitudinal passages through which gasunder pressure is directed to flow across the contact surfaces duringseparation thereof, operating means forthe movable contacts comprising across head member operatively connected to each of said movable contactsand guided for movement within the corresponding passage, a pistonconnected to said cross heads for causing simultaneous opening'of themovable contacts, means including a plurality of ports adapted tocommunicate with a source of pressure for directing gas under pres--sure to said piston to cause switch opening movement thereof, and meansrelated to said piston for successively closing said Ports during theswitch opening movement whereby the gas acting on said piston isgraduallythrottled.

3. In a circuit breaker of the gas blast type wherein a single source ofgas pressure is utilized to effect opening of the circuit andinterruption of arcing comprising a plurality of poles, each pole havinga stationary and movable contact and a tubular insulating member forminga passage for directing a gas under pressure across the contact surfacesof the contacts during separation thereof, said contact surfaces beingdisposed at the exhaust ends of said insulating members, operating meansconnected to each of said movable contacts, an operating piston having ahollow piston rod causing simultaneous opening of the contacts, meansincluding ports-adapted to be in communication with a source of pressurefor directing gas through said hollow piston rod to the piston to causeswitch opening movement thereof, 125 said hollow piston rod beingadapted to successively close said ports and throttle thegas acting onthe piston during its opening stroke, and a casing in communication withsaid source of pressure for concurrently directing a flow of gas at highi velocity through said tubular members and across the separatingcontact surfaces to extinguis arcing therebetween.

4. A circuit breaker unit of the gas blast type wherein a single sourceof gas pressure is utilized to effect opening of the circuit andinterruption of arcing comprising a pair of relatively movable contactsincluding a stationary nozzle-like .contact and a coacting rod contact,a' hollow insulating casing on which said stationary contact isfimounted, said casing forming a passage through which gas isdirected athigh velocity through said stationary contact and across the coactingcontact surfaces to extinguish arcing, a piston operatively connected tosaid rod contact, said 14 piston being in communication with a source ofWERNER UEBERMUTH.

